JPH03272805A - Manufacture of rod-shaped ceramic article - Google Patents

Abstract

PURPOSE:To efficiently obtain a ceramic article having high dimensional accuracy by forming specific depth recessions in the radial direction of a rod-shaped molding, and arranging them parallelly in contact with each other, and then breaking them at the recessions after baking. CONSTITUTION:Alumina powder is employed as a main component, and it is added with clay and other additives as well as water for kneading and, there after, cylindrical moldings of 2 mm and 4 mm in diameter are obtained by an extruding method. With respect to these cylindrical moldings 1, approximate ly V-shaped grooves 2 of 0.10, 0.15, 0.20, 0.25 mm in depth are formed on their peripheries, for example, at distances of 10 mm and 20 mm and, after that, these moldings 1 are arranged parallelly in contact with each other and baked for two hours at the temperature of 1,350 deg.C. And, the baked moldings obtained in this manner are broken by the use of a breaking jig in order to obtain cylin drical ceramic moldings. In the case wherein the depth of groove ranges from 1/3 to 1/4 and in the case wherein the moldings are arranged parallelly in con tact with each other during baking period, curvature is small as 50mum or below, and the breakage conditions in its ends becomes excellent.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing rod-shaped ceramic products such as ceramic rods and ceramic shafts used as switching push rods and resistors, for example. E. Prior Art Conventionally, cylindrical ceramic products used as switching push rods, resistors, and L5s are manufactured by cutting a cylindrical molded body by extrusion into a desired length and then firing it. ing.

[Problem M that the invention attempts to solve]

By the way, in the conventional manufacturing method, in order to prevent cracks and chipping defects after cutting, cutting is performed at a temperature of 1.7 while the molded body has plasticity (before firing). As shown in FIG. 3, the cutting blade 5 bites into the molded body 6, causing a bulge (bulge) 7 at the end of the molded body 6. Also, due to the bulge E caused at the time of cutting. If these are arranged in δ and t for firing, both ends of the molded body will be grounded but the center will be floating, and if fired in this state, the floating center will be Therefore, when a molded body with this bulge is sintered, only a shape with swollen ends and a curved center can be obtained, resulting in dimensional irregularities. not good. A first object of the present invention is to provide a rod-shaped ceramic product that has no bulges at the ends or bends at the center and has high 11 method accuracy. A second object of the present invention is to provide a rod-shaped ceramic product with high dimensional accuracy and efficient work.

[Means to solve the problem]

The object of the present invention is to provide 1 part of the effective diameter in the radial direction of the rod-shaped molded body.
Forming a recess with a depth of 730 to 1/4 in the rod-shaped molded body,
These are lined up so that they are in parallel contact with each other and fired, and after fS, the rod-shaped ceramic products are manufactured by the nona method, which is characterized by breaking at the recessed portion 0r1. The first example is a cylindrical ceramic product, but depending on the application, other products such as an elliptical cylindrical ceramic product, a prismatic ceramic product, etc. can be considered. And, what is the effective diameter of a rod-shaped molded body? If the rod-shaped molded body is cylindrical, it is the diameter of Pl of the cylinder.
In the case of an elliptical columnar shape or a prismatic columnar shape, when converted to a cylinder, the diameter of a circle (J) is the diameter of a circle. It is preferable that the recesses be formed around the periphery of the rod-shaped molded body, ie, 1"l:, but they may be formed partially such that there are breaks i and ε.

[Function] Unlike the conventional method, in the present invention, only the recessed portions are formed without cutting the molded body, so that there is extremely little bulge caused by bulging. Here, the depth of the recess is 1. If it is significantly smaller than /30, when it breaks after firing, it will be cracked diagonally or in parts other than the recessed parts, which is ineffective. On the other hand, if the depth of the recess significantly exceeds the effective diameter of 174, a bulge 1-4 will be formed inside the recess. When sintering, if the molded bodies are arranged in parallel contact, the contact areas between the molded bodies become parallel lines with each other, so bending during the sintering process is extremely small. After adding clay and other additives and water to this and kneading it, it was extruded to a diameter of 2wn.
), H4ma+ cylindrical molded bodies were obtained. For these cylindrical molded bodies 1, as shown in FIG.
10muah 0.10.0.1 at intervals of 20 gates
After forming a cylindrical shape with a depth of 5.020° 0251°, the It shapes 1 were arranged in parallel and in contact with each other, and fired at 1350° C. for 2 hours. The fired product thus obtained was fractured using a fracture method to obtain a cylindrical ceramic product. As shown in the second diagram, the dimensional accuracy of the cylindrical ceramic product Table 1 shows the results of observations of the following sizes and shapes using a four-saw projection machine. Table 1 *In Examples 5 and 6, the grooves 2 were formed at the stage when the cylindrical molded body was sufficiently dried and the variable +3 was lost. Other field names were determined at a stage where the molded body 1 was variable. *In Comparative Example 3, in Example 1, the molded bodies 1 were arranged in parallel and in contact with each other and fired at 1350°C for 2 hours, whereas in Example 1, the molded bodies 1 were arranged unevenly and the temperature was 5.135.
The molded body was fired for 2 hours at 0''C. When the grooves are lined up so that they are in contact with each other, the bending is small at 50 μm or less, and the breakage at the edges is also good. In this case, not only did the bending become large (76 μm), but also a bulge was caused at the end.When the depth/diameter of the pipe is small, such as 0.025, the bending is small, but the end becomes bulged. It was defective because it broke diagonally.Also, 1/3 (1-1/4) of the effective diameter in the radial direction of the rod-shaped molded body
Even if a recess with a depth of
If the molded bodies are not arranged parallel to each other so that they are in contact with each other, but are arranged unevenly, the bends will be thick (and the features of the present invention will not be achieved.) [Effects of the Invention] , a concave portion having a depth of 1/30 to 1/4 of the effective diameter is formed in the rod-like molded body in the radial direction of the rod-like molded body, and the concave portions are arranged in parallel and in contact with each other and fired; Break at position Uf1''
Therefore, it is possible to efficiently obtain a highly accurate ceramic product with no bulges at the ends of the rod-shaped ceramic products and no bends in the center.

[Brief explanation of drawings]

Figure 1 is a schematic perspective view showing the manufacturing method of the rod-shaped ceramic product according to the present invention, the second figure is a schematic diagram showing the degree of bending of the cylindrical ceramic product, and Figure 3 is the conventional rod-shaped ceramic product. It is a schematic W@ diagram showing defects in the manufacturing method of ceramic products. 1. Molded body (rod-shaped molded body), 2... clear concave part).

Claims (1)

[Claims] A concavity with a depth of 1/30 to 1/4 of the effective diameter is formed in the rod-shaped molded body in the radial direction of the rod-shaped molded body, and the rod-shaped molded body is lined up in parallel and in contact with each other and fired, and then broken at the position of the recess. A method of manufacturing a rod-shaped ceramic product characterized by the following.